Apparatus for making tape reinforced plastic pipe



Oct. 8, 1963 T. P. LEWIS ETAL 25,457

APPARATUS FOR MAKING TAPE REINFORCED PLASTIC PIPE 4 Sheets-Sheet. 1

Original Filed Oct. 8, 1956 INVENTORS THOMHS P LEWIS wu usw ATTORNEYSOct. 8, 1963 -r. P. LEWIS ETAL 25,457

APPARATUS FOR MAKING TAPE mzmroacsn PLASTIC PIPE Original Filed Oct. 8,1956 4 Sheets-Sheet 2 3% 2 a l .F F.' =3 F m *2 s A TORAIE vs Oct. 8,1963 T. P. LEWIS ETAL Re. 25,

APPARATUS FOR MAKING TAPE REINFORCED PLASTIC PIPE Original Filed Oct. a,1956 4 SheetsSheet 3 INVENTORS THOMAS P Lewas BY DOV HENIS #M 6. 4,.i-SW ATTORN EYS Oct. 8, 1963 T. P. LEWIS ETAL 25,457

APPARATUS FOR MAKING TAPE REINFORCED PLASTIC PIPE Original Filed Oct. 8,1956 4 Sheets-Sheet 4 United States Patent Office Reissued Oct. 8, 196325,457 APPARATUS FOR MAKING TAPE REINFORCED PLASTIQ PIPE Thomas 1.Lewis, North Apollo, and Dov Henis, Pittsguggh, Pa, assignors to MyronCohen, New York, Original No. 3,004,585, dated Oct. 17, 1961, Ser. No.614,729, Oct. 8, 1956. Application for reissue June 5, 19:52, Ser. No.2%,616

13 Claims. (Cl. 156-425) Matter enclosed in heavy brackets [1 appears inthe original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates to a method and apparatus for making reinforcedplastic hollow members and more particularly for making fiberglassreinforced plastic hollow members such as pipes, conduits and so forth,which may either be circular in cross section or in some polygonal form.Most particularly, the invention relates to a method for makingfiberglass reinforced plastic pipe.

Fiberglass reinforced plastic pipe has been known heretofore and itshighly desirable properties have been fully appreciated. Among theadvantages of using fiberglass reinforced plastic pipe, hereinafterreferred to as plastic pipe, are the ease of handling due to the lightweight, the corrosion resistance and the ease of connecting sections ofsaid pipe together. Unfortunately, the advantages of plastic pipe havenot been fully realized because of the present excessive cost ofmanufacturing such pipe. The major reason for the prohibitive cost ofsuch pipe is due to the fact that no simple fully automatic method beendevised for its manufacture.

initially, plastic pipe was made by winding plastic impregnatedreinforcing tape on a slightly tapered cylindrical form, curing theplastic and thereafter removing the cured pipe from the cylindricalform. This was a completely manual operation and the costs of labor wereso high as to render the ultimate price of the finished productprohibitive. Moreover, the pipe took on the slight taper of the form.Subsequently, machines were developed which automatically wind plasticimpregnated fiberglass tape onto a mandrel. Although such machinesreduce the cost of manufacturing plastic pipe, it is still necessary tomanually remove the plastic pipe from the mandrel and often this removalis effected by disengaging the mandrel from the winding machine andthereafter rcmoving the pipe therefrom. A new mandrel is thensubstituted for the one on which the pipe has been formed. In additionto the excessive costs of the method hereinbeforc described, it will beobvious that by using such methods plastic pipe could only be made indiscrete lengths, the length being determined by the length of themandrel.

Another method of manufacturing plastic pipe is by a slush castingmethod which has been ordinarily used to make large diameter piper.Unfortunately, the slush casting method is completely unsuitable formaking anything but vci'y short lengths of pipe and this method ofmanufacturing the short lengths of pipe is extremely expensive.

The present invention is directed primarily to the provision of a newmachine which will manufacture reinforced plastic pipe or tubing atextremely low cost and this is the major object of the presentinvention.

Another object of the present invention is the provision of a newmachine for manufacturing plastic pipe which is adapted to make acontinuous pipe of any desired length, be it feet or miles.

A further object of the present invention is the provision of apparatusfor making plastic pipe which will have an extremely smooth interiorsurface to thereby reduce friction between it and the fluids flowingtherein.

Still another object of the present invention is the pro vision of afully automatic machine to manufacture plastic pipe.

Yet a further object of this invention is the provision of a novelmandrel which has a continuously progressively movable surface toadvance plastic pipe lengthwise therewith and thus form a means ofmanufacturing plastic pipe of indefinite length.

The above and other objects, characteristics and features of the presentinvention will be more fully understood from the following descriptiontaken in connection with the accompanying illustrative drawings.

in the drawings:

HO. 1 is a side elevational view of an automatic machine for makingfiberglass reinforced plastic pipe in accordance with the presentinvention;

FIG. 2 is a longitudinal sectional view the machine shown in FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is an end elevational view of the machine shown in FIG. 1 withparts broken away to more clearly illustrate other parts of saidmachine;

FIG. 5 is an enlarged fragmentary perspective view of portions of themandrel included in the machine forming the present invention;

FIG. 6 is a diagrammatic view of the path of movement of a flexiblewrapper forming a part of the present invention;

FIG. 7 is a perspective view with parts broken away illustrating theproduct formed by the present invention;

FlG. 8 is a view similar to FIG. 5 illustrating another form of thepresent invention;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 2;

FIG. 10 is a fragmentary perspective view illustrating details of aportion of the drive means included in the present invention;

FIG. 11 is a view similar to FIG. 10 showing another modification of thepresent invention.

Referring now to the drawings in detail, the machine for makingfiberglass reinforced plastic pipe is generally designated by thereference numeral 10. This machine comprises a stationary base 12 havinga cylindrical portion 14 extending transversely of the base and actingas a support for the various elements of the machine. Supported directlyand indirectly by the base portion 14 is a rotating mandrel 16, a pairof movable spool holders 13 and 2t and a fixed spool holder 22. A fixedspool holder 24 is supported by the base 12 through a bracket 25. Thespool holders are adapted to hold spools of reinforcing tape and tosupply said tape to be wrapped around said mandrel whereby to form areinforcing network for a plastic pipe.

of a portion of The reinforcing tape may be any suitable flexible typeof material and fiberglass is presently preferred. Most preferably, thetape is a fiberglass roving, although a woven fiberglass may be used aswell as rovings and woven tapes of other reinforcing materials. Thereasons why we presently prefer a roving will become more apparent asthis description proceeds.

The movable spool holder is fixed to a cylindrical sleeve 26 which isrotatably mounted on the cylindrical base part 14 as by bearings 28carried by a bearing support 29 fixed to base 12. A gear 30 is fixed tosleeve 26 and is in meshed relationship with a drive gear 32 whichimparts rotary movement to gear 30 and hence to sleeve 26, whereby toimpart rotary movemint to spool holder 20. Another sleeve 34 is movablymounted concentrically of the base 14 and is disposed within thecylindrical portion 14 of the base 12. As shown herein, sleeve 34 hastwo spaced concentric cylindrical portions 35 and 36,

portion being in operative engagement with bearings 37 which also engagestationary part 14 of base 12. The space between cylindrical portions 35and 36 is designated 38 which provides a passage for the fiberglassroving carried by the spool holder 18 mounted on cylindrical part 36.The sleeve 34 carries a gear 42 mounted at the left hand end of part 35,which is in meshed relationship with a drive gear 44 to impart rotarymovement to the spool holder 18 and to sleeve 34. As will become clearhereinafter, spool holders l8 and 20 preferably rotate at the sameangular velocity.

Disposed concentrically within the sleeve 34 and spaced therefrom isanother fixed cylindrical member 46 which is separated from the sleevepart 36 by bearings 48. Fixed cylindrical member 46 is actually made upof two fixed cylindrical members 50 and 52 which are concentric andwhich are spaced from one another by guide ridges 53 to provide achannel or path for a flexible wrapper and a separator therefor as willbe described in more detail hereinafter. Mounted on the innercylindrical part 52 of cylindrical members 46 are ball bearings 54, theouter races of said ball bearings being connected to the stationarycylindrical member 52 and the inner races thereof being connected to afixture 56 which surrounds and is connected to a longitudinallyextending rotatable pipe or cylindrical member 60 forming part of themandrel 16. Fixture 56 is in fact a cylindrical shaft having internalridges or splines 61 extending longitudinally thereof, the free surfacesof said splines being fixed to the external surface of tube 60 in anysuitable manner so that the two parts rotate in unison (see FIG. 9). Thesplines 61 define therebetween passages 63 for a purpose which willbecome clear as this description progresses.

The longitudinally extending pipe 60 is the basic forming element forthe plastic pipe to be made by the machine 10. The length of the pipe 60is not critical but as will become apparent hereinafter, pipe or tubularmember 60 must be sufficiently long to give the plastic pipe which isformed thereon an opportunity to be at least partially cured prior toremoval therefrom in a manner to be described hereinafter in order to beable to maintain its form. Tubular member 60 is rotated through themedium of a fixture 62 which is fixedly connected to the tube 60 bymeans of tines or fingers 64 which are pressed to fit internally intothe tube 60. The fixture 62 is pro vided with a plurality of outwardlyextending fingers or finger portions 65 which are fixedly connected toan adapter 66 in the form of a continuous ring. Carried by the adapterring 66 is a ring gear 67.

Referring now to FIG. 4, the ring gear 67 is in meshed relationship witha spur gear 68 which extends through registered slots 69 in cylindricalportions 50 and 52 of sleeve 46. Gear 68 is driven by a spur gear 70mounted on a shaft 71 which has provided thereon another spur gear 72which rotates in unison with gear 70. Gear 72 is driven by a gear 73mounted on a shaft 74 which carries a gear 75 which rotates in unisonwith the gear 73. Gear 75 is in meshed relationship with a ring gear 76which is fixed to sleeve 34 and rotatable therewith. As shown in FIG. 2,ring gear 76 is located adjacent the extreme left hand end of sleeve 36.By employing the train of gears as described above, when gears 32 and 44rotate in a manner to be described presently, rotation is imparted tosleeves 34 and 26 and from sleeve 34 through the last mentioned geartrain including elements 67 to 75, adapter 66 is rotated and therebyimparts rotary movement to fixture 62 and tube 60 forming the mainportion of mandrel 16. To impart rotary movement to gears 32 and 44, amain drive shaft 77 carrying a pulley 78 is mounted on Ease 12. Pulley78 is driven by a belt 79 from a suitable motor means (not shown) torotate the main shaft 77. Carried by the main shaft 77 is a spur gear 80which is in meshed relationship with another spur gear 81 mounted on ashaft 82 which is also carried by the base 12. Fixed to the shaft 82 isanother spur gear 83 which is in meshed relationship with :a spur gear84 carried by a drive shaft 85. Gears 32 and 44 are fixed to the shaft85 and, accordingly, they rotate in unison with the gear 84. In thismanner power is provided from the motor means to the plurality ofrotatable elements in machine 10.

In accordance with one highly desirable feature of the presentinvention, means are provided on the surface of the forming member ortubular member 60 which move longitudinally of said tubular member.Accordingly, and as will become more apparent hereinafter, when theplastic impregnated fiberglass roving is wound onto the mandrel 16, itmoves longitudinally thereof and by suitable heating means is curedwhile moving longitudinally of said mandrel and after being cured ismoved off said mandrel, whereby to provide for a continuously formedpipe unachieved heretofore. As shown herein and as is presentlypreferred, the movable means on the mandrel 16 C0111- prises a pluralityof continuous conveyor elements here shown as continuous ribbons 86which extend longitudinally of the pipe 60 along the outer surfacethereof and also extend through said tubular member 60 between it andthe outer surface of a fixed tubular member 87. Other flexible memberssuch as chains or belts may be used. The plurality of ribbons 86, hereshown as eight in number, engage at each end roller means, shown inFIGS. 1, 2, 3, 5 and 10 as rollers 88 and 89 although chain sprockets orother roller means may be employed. Rollers 88 and 89 are operativelyrotatably mounted on the tubular member 60. As shown herein,particularly in FIG. 10, the rollers 88 are rotatably mounted on axles90 which extend between adjacent spaced arms 64 of the fixture 62. Therollers 89 are rotatably mounted on axles 91 which are mounted in asuitable fixture 92 fixed to the right hand end of the tubular member68. In a manner to be described below, the rollers 88 are positivelydriven to thereby rotate and move the ribbons 86 longitudinally of thetubular member 60, the rollers 89 acting as guide and idler rollers. Theribbons 86 pass between rollers 88 and 89 through passages 63 defined bysplines in fixture 56. The direction of rotation of the rollers 88 issuch that the portions of the ribbons 86 overlying the outer surface ofthe tubular member 60 move in a rightwise direction as viewed in FIG. 2.

In order to rotate the driver rollers 88, driver rollers 93 are infrictional engagement with the portions of the ribbons 86 in engagementwith the driver rollers 88. The rollers 93 have integrally formedthereon a worm gear 94, the entire assembly rotating on axles 95extending between the arms 64 of the fixture 62. The worm gears 94 arein meshed relationship with worm wheels 96 which are fixed to shafts 98rotatably mounted in the fixture 62. Fixed to the left hand ends of theshafts 93 are planetary gears 162 which are all in meshed relationshipwith a sun gear 184 fixed to a fixed tubular member 87. Accordingly,when the motor means is actuated to operate the gear trainsaforedescribed to thereby impart rotary movement to the tubular member60 and fixture 62 about their longitudinal axes, planetary gears 102will rotate therewith about the axis of fixture 62 and due to theirengagement with the fixed sun gear 184 will rotatae about their own axesto impart rotary movement to the shafts 98 about their respectivelongitudinal axes, and thereby impart rotary movement to worm gears 96to rotate drive rollers 93 and thereby impart rotary movement to rollers88 and linear movement to the ribbons 86. To maintain hollow shaft 87fixed, a bracket 105 is fixed at one end to fixed shaft 87 and fixed atits other end to fixed sleeve portion 52 of sleeve 46. By means of thegear drives aforedcscribed, spools 18 and 28 are preferably caused torotate at twice the angular velocity of the tube 60 and in the samedirection. The purpose for this will become clear hereinafter. Suificcit to say at this point that many other types of drive mechanisms may beemployed and the present invention is not limited to the one illustratedin W6. 3. Moreover, as will become apparent as this descriptionprogresses, the ratio of speeds oi the spool holders to the mandrel isnot necessarily 22l and other suitable ratios may be employed.

As stated hereirtbeforc, in the mechanism 19 illus tratcd in thedrawings there are four spool holders 1S, 2%, 22 and 24, spool holders13 and 23 being rotatable about the longitudinal axis of the mandrel 16at twice the rotational speed thereof and spool holders 22 and 24 beingstationary. Each of the spool holders 13, 2t), 22 and 24 is adapted tocarry a spool of fiberglass roving 122, 124, 12.6 and 123, respectively,said spools being rotatably mounted in said spool holders. Thefiberglass roving 122 is brought onto the mandrel 16 in a spiral pathextending from the spool holder ill to the mandrel 16 around the innercylindrical part as of the rotatable cylindrical member 34, it beingdisposed in the space 33 between the cylindrical parts 35 and 36 of thesleeve 34, the path being defined by a helical guide ridge 130-. Thefiberglass roving 12!) which comes off the stationary spool holder 22 isbrought onto the mandrel 16 in a spiral path in which the roving 126overlies the outer surface of the stationary cylindrical part 14 of thebase 12 in helical form defined by helical guide ridge 12.9. Resin froma reservoir 132 is supplied to roving 126 through a passage 13 i. Roving124 passes oil the spool and winds around sleeve 2.! in a helical pathdefined by helical guide ridge From the sleeve 26 the roving moves ontothe mandrel 16 on which it is wound in the form of a helix. The roving123 which is supplied from spool holder 24 which is fixedly supported bybase 12 is wound directly from the spool holder 2 to the mandrel 16. Inpassing from the spool holder to the mandrel, the roving 128 comes intoclose relationship with a suitable resin supply 137 whi'h is supplied byresin reservoir 135 to impregnate roving 128.

As is cle. rly shown in MG. 2, roving 122 which is not impregnated withresin, is the first or bottom layer of the pipe laid down onto themandrel 16. Since, with the motor means energized, the surface of themandrel for all intents and purposes is moving longitudinally thereofdue to the movement of ribbons and is rotating at a given angularvelocity and roving 122 is rotated with sleeve at twice said angularvelocity and in the same direction, the roving 122 is formed onto themandrel in a spiral wound in a given direction. The

arts are proportioned to move at such speeds that the edge of the rovingis disposed at an angle to the vertical which is substantially e "ll to2534. Assuming the roving is three inches v it will be desired that 3.82convolutions of the spiral will be laid onto the mandrel per foot withabout /6 inch overlap on each adjacent convolution. These figures arepresented as being the most desirable or reasons of strength will bedescribed more clearly subsequently, and it will be obvious that otherspeeds and angular dispositions may be selected if desired.

The second layer of the pipe is formed of a spiral extending in theopposite direction or being angularly related to the spiral defined bythe roving 122 and being disposed also at an angle of 2634 to thevertical. The second layer, formed of the roving 126 is, as statedhereinbe'iore, impregnated with pie or resin, the impregnation being toa sui. cient do so that when the roving 126 is wound onto the mandreland overlies the roving 1Z2, resin from the roving 125 lows into theroving 122 to impregnate the latter. Roving 126 is fed to the mandrelfrom a stationary means whereby the spiral it forms on mandrel in iswound in the oppos e direction to the spiral formed by roving 122.. ofthe plastic pipe 14% with the additional two ls. ers 1.24 and 123 issubstantially the same as that for layers 122 and lilo whereby to make afour-ply pipe 14 with all of the consubstantially volutions disposed atangles to the vertical equal to 2634, and the resin from the rovings12.6 and 128 causing resin impregnation of the rovings 122 and 124. Asstated above, two of the layers are wound in one direction and the othertwo layers are wound in the opposite direction. It will be seen that asthe rovings are laid onto the mandrel, due to the longitudinal movementof the ribbons 86, the spirally wound rovings will move to the right asviewed in FIG. 1. As they move to the right they will be subjected toheat from a suitable heating means 139 in close proximity to themandrel, whereby to cure the resin and after curing the plastic pipe 40continues to move longitudinally of the mandrel and oil the mandrel,whereby to make room for additional lengths of the same pipe 140. Itwill be seen therefore that the pipe 140, since it is constantly movingto the right due to the movement of the ribbons 86, can be made as longas is desired, there being no limits since when the spools for theseveral rovings are exhausted, new rovings can be secured thereto, andas the resin reservoir is depleted additional resin may be suppliedthereto also.

As stated hereinbefore, we presently prefer to use a roving rather thana woven tape. We choose a roving since with all the fibers extending inthe same direction we achieve far greater strength in a peripheraldirection than can be achieved with a like amount of material in a woventape.

Moreover, we presently prefer to wind the roving at angles of 2634 tothe vertical because at this angle the reinforcing roving tends to givetwice the reinforcement in the peripheral direction than is given in thelongitudinal direction and since plastic pipes of the type shown in FIG.7 and designated 140 are normally subjected to much greater peripheralstresses than to longitudinal stresses, at light weight pipe of suitablestrength can be achieved when the rovings are disposed at said angles.Of course, if peripheral strength is not a critical factor, other anglesmay be used.

The resin utilized to manufacture the plastic pipe may be any suitablethermosetting or thermoplastic resin. We presently intend to use epoxyresins and polyester resins and polyester resins are presentlypreferred. it will be obvious that the heating means 139 surrounding themandrel for curing the resin must be able to subject the pipe 140 tosutficiently high temperatures to cure the type of resin being employedand should be long enough, taking into account the linear speed ofribbons 86, to fully cure the resin.

An alternative means for heating pipe 140 to effect the curing of theresin is to provide in addition to heating means .139, an internalheating means 141 disposed between rotating member 60 and fixed member87. Heat ing means 141 is preferably designed to heat the inner portionof pipe or tube 140 to a slightly higher temperature, of the order of 50F., than the heating means 139 heats pipe 140. This will cause a flow ofthe resin toward the innermost layer of fiberglass roving to render saidlayer resin-rich. The concentration of resin in the innermost layer willrender said layer highly resistant to corrosion whereby to greatlyincrease the life of the pipe 140.

The embodiment of the invention described hercinbefore will operate inthe described manner. However, there are a number of disadvantages tothis construction which can be obviated by the addition of a flexiblewrapper 142 in a manner to be described presently. The disadvantages ofthe structure described above result from the fact that if the bottomlayer or roving 122 is wound directly onto the plurality oflongitudinally movable ribbons 86, there will be of necessity anirregular inner surface in the pipe 140, which irregular surface willtend to increase the amount of friction to fluid flow therein. Moreover,there is a distinct possibility of clogging due to resin getting betweenthe outer surface of the longitudinally extending tubular member 60 andthe ribbons 86, whereby to prevent efficient operation of the mechanismor possibly to discontinue operation entirely.

In order to obviate these dilficulties, and as stated hereinbefore, aflexible wrapper 142 is used. The flexible wrapper may be of anysuitable material which will not adhere to the resin, but preferably theflexible wrapper is made of steel. The flexible wrapper is wound ontothe mandrel 16 to overlie the ribbons 86 in an overlapping spiral,whereby to prevent any resin from coming in contact with the ribbons orthe longitudinally extending tubular member 60. If desired, the Wrappermay merely be carried on a spool and taken off the spool due to therotation of the mandrel and gathered up at the opposite end of themandrel by another spool which rotates at a suitable angular velocity.It will be obvious from a perusal of FIG. 6 that the wrapper 142underlies the bottom layer of fiberglass roving 122 and therebyseparates it from the ribbons and tubular member 60. Since the wrapper142 may be extremely thin, the overlap from convolution to convolutionwill cause little surface irregularity on the inner surface of the pipe140 and thereby give it excellent flow characteristics as well as toprevent clogging of the mechanism with the resin. Although the metalwrapper does not readily adhere to the resin, in order to insure nofouling of the metal wrapper, a suitable separator is supplied to thewrapper prior coming into engagement with the bottom layer 122 ofroving. This separator is supplied from a separator supply reservoir 144through a channel 146 extending between the two fixed tubular portions50 and 52 of the sleeve 46. At the right hand end of the channel 146 isan applicator 148 which has a passage 150 extending from the channel 146to a suitable pad 152 which may be made of felt, foam rubber or otherlike material. The pad 152 engages the wrapper 142 as it is first woundonto the mandrel 16 at the left hand end thereof and coats it with asuitable separator such as a silicone grease in order to preventadhesion of the wrapper to the resin. Although silicone grease ifpreferred, other hydrocarbon greases may be employed.

As is now presently preferred, in lieu of a hydrocarbon greaseseparator, wrapper 142 is thinly permanently coated withpolytetrafluoroethylene, polytrifluorochloroethylene, or other similarmaterial. Materials of this type are inert and thereby act as an idealseparator. Moreover, once the wrapper is coated with such material, theneed for a separator supply is obviated, thereby eliminating the expenseof providing such supply and the need for periodically refilling theseparator reservoir. If desired, wrapper 142 may be made wholly ofpolytetrafluoroethylene, polytrifluorochloroethylene or the like.

Although the manner of supplying and withdrawing the wrapper 142 fromthe mandrel 16 as described above will operate satisfactorily, it hasthe shortcoming of requiring a shutdown of the machine each time a spoolof wrapper is exhausted whreby to prevent continuous automaticmanufacture of pipe. To obviate this shortcoming and as one of thehighly desirable features of the present invention, we have devised acontinuous wrapper. The path of movement of the continuous wrapper willnow be described: Starting from the applicator 148 the wrapper is woundspirally about the mandrel in overlying relationship with the ribbons 86and naturally moves with said ribbons longitudinally of the mandrel. Atthe extreme right hand end of the mandrel where the wrapper will tend tomove off the mandrel 16 and separate from the pipe 140 being formedthereon, the wrapper is directed through open right hand end of the tube87 into the interior of said tube 87. In so directing the wrapper it iswound into a spiral in which the convolutions extend in the oppositedirection to that portion of the wrapper overlying the mandrel. In FIG.6 the spirally wound portion of the wrapper 142 overlying the mandrel isreferred to as 142a and the reversely wound wrapper portion disposedwithin the shaft 87 is designated 142b. The portion 142b extends theentire length of the hollow shaft 87 interiorly thereof and moves to theleft relative thereto in a manner which will become clear presently. Atthe left hand end of the portion 142b of wrapper 142, the wrapper passesout of the shaft 87 through the left hand end opening thereof. From theleft hand opening the wrapper passes through a cut-out portion 143 inpart 52 of sleeve 46 to helical guide ridge S3 defined on the inner part52 of the fixed cylindrical member 46. This helical guide ridge guidesthe wrapper around said portion 52 to the right hand end thereof wherethe wrapper 142 extends upwardly to the separator. All the variousmovements of the continuous wrapper are imparted thereto due to thelongitudinal movement of the portion 142a in the rightwise direction asimparted by the ribbons 86. Since the portion 142a is constantly movingto the right, it will require placement from the portion of the ribbondesignated 142c which is disposed in the helical groove 53 and since theportion 142c will accordingly move longitudinally of said groove, itwill constantly draw the spirally wound portion .142b to the left,thereby constantly supplying a new portion of the wrapper to make it thepart 142c. In this manner the wrapper need never be replaced or made upwith additional spools and so forth, the wrapper 142 becoming anintegral part of the apparatus.

Referring now to FIG. 8, a modification of the present invention isillustrated. In this modification the roller means disposed at both endsof the mandrel 16 are rotatable sprockets which are in operativeengagement with a plurality of suitable chains 182 having portionsextending over the surface of tubular member 60 and other portionsextending through the interior of tubular member 60. The chains operateas continuous flexible members in much the same way as do the ribbons 86described above. The manner for imparting movement to the driversprockets 180 may be similar to that employed for the driver rollers 88described above with necessary modifications well within the ability ofthose skilled in the art. It is believed that the operation of thismodification is clear from the description of the operation of theembodiment including the ribbons 86. It should be noted that whenemploying a mandrel 16 having chains extending along the surfacethereof, it is practically mandatory to employ a wrapper such as wrapper142 since the surface irregularities of any finished product made on amachine not including said wrapper would make the product commerciallyundesirable. It may be desirable to dispose the upper portions of thechains 182 within longitudinal recesses in the mandrel whereby to renderthe upper surfaces of the chains 182 just a slight bit out of flush withthe surface of the tubular member 60. One of the major advantages toemploying chains as the con tinuous flexible member in lieu of ribbonsis that an in creased amount of power may be supplied thereto to effectsmooth undisturbed movement of heavy pipe 140.

Referring now to FIG. 11, another modification of the present inventionis illustrator]. In this modification, the drive ribbons 86 aresubstantially identical to the driving ribbons 36 heretofore describedwith the exception that they are provided with a plurality of apertures200' which are spaced longitudinally along the ribbons 86'. Theapertures 200 are engaged by cogs 202 on the surface of the roller 88'.Roller 88' is provided at its ends with spur gears 204 which are inmeshed relationship with spur gears 206 respectively fixed at oppositeends of worm wheel 94'. Worm wheel 94' is in meshed relationship withworm 96' which may be rotated in the same manner in which worm wheel 96in FIG. 10 is rotated, as was described hereinbefore. With thearrangement shown in FIG. 11, ribbons 86' are positively driven by meansof the cogs 202 and the apertures 200 whereby to insure against slippagewhen the machine is operating under load.

It will be obvious in view of the foregoing paragraph that link belts,timing belts, and other suitable types of continuous flexible membersmay be employed as conveyor elements to eifect longitudinal surfacemovement along the mandrel 16 Without departing from the spirit andscope of the present invention.

Various other features and modifications of the basic mechanismdescribed hereinbefore may be employed. For instance, a superioruniformity of resin impregnation is achieved if prior to the rovings 126and 128 being immersed in the resin they are heated as by passingbetween a pair of parallel heated plates 160.

Another highly desirable modification of the present invention is thesubstitution for the bottom layer of roving 122 by a ribbon ofthermoplastic material which will provide the plastic pipe 140 with acorrosion and waterproof lining to prevent weep as might occur ifpolyester were used to impregnate the rovings. Examples of suitablethermoplastics are polyvinyl chloride and polyethylene. The operation ofthe machine Will be precisely the same save for the substitution of thethermoplastic ribbon for the roving 122.

In accordance with another modification of the present invention, theinner and outer surfaces of the pipe formed by machine may be overlayedby random. oriented fiber, either natural or synthetic. We presentlyprefer synthetic fibers and most preferably prefer random orientedacrylic fibers. These fibers may be introduced into the pipe in the formof a tape made up of random oriented fiber and preferably either priorto or at the time of introduction onto the mandrel the fibers areimpregnated with resin, preferably the same resin as is used toimpregnate the fiberglass rovings although different resins may beemployed. By incorporating inner and outer layers of random orientedimpregnated fibers, We have found that the corrosion resistance anderosion resistance of the final product are greatly increased over thatpossessed by a pipe having only layers of impregnated rovings.

It is also Within the scope of the present invention to make the entiremandrel and associated parts removable and replaceable as a unit,whereby to adapt a single machine 10 to make plastic pipes of dilerentdiameters.

A machine 10 embodying some or all of the features described herein hasvast utility. Not only may it be permanently located in a factory aswould be expected, but it can readily be mounted on a vehicle tomanufacture pipe and lay pipe directly from the end of the mandrel, thevehicle moving at a rate to let the pipe fall smoothly into place. Thiswill not only result in a vast speedup in pipe laying procedure, butwill obviate the necessity of shipping bulky pipe to the site Where itis to be laid, only the relatively compact raw materials needing to beshipped.

Although the machine 10 together with all the modifications thereof havebeen described as being used in conjunction with a cylindrical mandrel,it will be understood that the present invention may be readily employedto manufacture rectangular and polygonal pipe. All that need be done toadapt the machine for such use is to shape the main mandrel member 60into the form desired for the final product. That is, if a square pipeis desired, member 60 should be square and if a hexagonal pipe isdesired, member 60 should be hexagonal in cross section. With this onechange the mandrel construction described hereinbefore may be employedto make the final product.

Having thu described this invention, it will be obvious that variouschanges and modifications maybe made there in within the scope of theappended claims without departing from the spirit and scope of thisinvention.

What We claim is:

1. In apparatus for making tape reinforced plastic pipe, a mandrelcomprising a longitudinally extending tubular member, a plurality ofcircumferentially spaced rollers disposed adjacent one end of saidtubular member, another plurality of circumferentially spaced rollersdisposed adjacent the other end of said tubular member, a plurality ofcontinuous ribbons having circumferentially spaced portions overlyingthe outer surface of said tubular member and having othercircumferentially spaced portions extending through said tubular member,each of said ribbons operatively engaging a roller at each end of saidtubular member, and means for rotating the plurality of rollers at oneend of said tubular member for imparting linear movement to saidribbons.

2. In apparatus for making tape reinforced plastic pipe, a mandrelcomprising a longitudinally extending rotatable tubular member supportedadjacent only one end thereof, means for rotating said tubular memberabout its longitudinal axis, a plurality of circumferentially spacedrollers disposed adjacent one end of said tubular member and beingrotatable about axes extending transversely of the longitudinal axis ofsaid tubular member, another plurality of circumferentially spacedrollers disposed adjacent the other end of said tubular member and beingrotatable about axes extending transversely of the longitudinal axis ofsaid tubular member, a plurality of continuous ribbons havingcircumfcrentiaily spaced portions overlying the outer surface of saidtubular member and having other circumferentially spaced portionsextending through said tubular member, each of said ribbons operativclyengaging a roller at each end of said tubular member, and drive meansopcratively connecting said plurality of rollers at one end of saidtubular member to said tubular member for imparting rotation to saidlast mentioned plurality of rollers about their respective axes inresponse to rotation of said tubular member about its longitudinal axisto impart longitudinal linear movement to said plurality of ribbonsrelative to said tubular member.

3. ln apparatus for making tape reinforced plastic pipe, a mandrelcomprising a longitudinally extending tubular member, a continuousribbon having a portion overlying the outer surface of said tubularmember and another portion extending through said tubular member, saidribbon being movable longitudinally of said tubular member, and awrapper spirally wound on said tubular member and overlying said firstmentioned portion of said ribbon, whereby when said ribbon moveslongitudinally of said tubular member, said Wrapicr moves along withsaid ribbon, said Wrapper being adapted to engage the inner surface ofsaid plastic pipe during the formation thereof for moving said pipetherewith and being disengageable from said inner surface of saidplastic pipe after formation thereof.

4. 1n apparatus for making tape reinforced plastic pipe, at mandrelcomprising a longitudinally extending tubular member, a continuousribbon having a portion overlying the outer surface of said mcn'iber andanother portion extending through said tubular member, said ribbon beingmovable longitudinally of said tubular member and a continuous Wrapperhaving a portion spirally Wound over the outer surface of said tubularmember and the portion of said ribbon overlying the outer surface ofsaid tubular member and having another portion extending through saidtubular mom :1, whereby when said ribbon moves longitudinally of saidtubular member the portion of said Wrapper overlying said tubular membermoves along with said ribbon and the portion of said wrapper disposedwithin said tubular member moves in the opposite direction, the portionof said Wrapper overlying said tubular member and ribbon being adaptedto engage the inner surface of said plane pipe during the formationthereof for moving said pipe therewith and being disengageable from saidinner surface of said plastic pipe after formation thereof.

5. ln apparatus for making tape reinforced plastic pipe, a mandrelcomprising a first longitudinally cxlcn ing tubular member, a secondlongitudinally extending tubular member disposed within said firsttubular member and spaced therefrom, a continuous ribbon having aportion overlying the outer surface of said first tubular member andanother portion extending between said first and second tubular members,said ribbon being movable longitudinally of first and second tubularmembers, and a continuous wrapper having a portion spirally wound overthe outer surface of said first tubular member and the portion of saidribbon overlying the outer surface of said first tubular member, andhaving another spirally wound portion extending through said secondtubular member, whereby when said ribbon moves longitudinally of saidfirst tubular member the portion of said wrapper overlying said firsttubular member moves along with said ribbon and the portion of saidwrapper disposed within said second tubular member moves in the oppositedirection, the portion of said wrapper overlying said first tubularmember and ribbon being adapted to engage the inner surface of saidplastic pipe during the formation thereof for moving said pipe therewithand being disengageable from said inner surface of said plastic pipeafter formation thereof.

6. In apparatus for making tape reinforced plastic pipe, :1 mandrelcomprising a longitudinally extending rotatable tubular member supportedadjacent only one end thereof, means for rotating said rotatable tubularmember about the longitudinal axis, a fixed longitudinally extendingtubular member disposed within said rotatable tubular member and spacedtherefrom a continuous ribbon having a portion overlying the outersurface of said rotatable tubular member and another portion extendingbetween said fixed and rotatable tubular members, said ribbon beingmovable longitudinally of said rotatable tubular member, and acontinuous wrapper having a portion spirally wound over the outersurface of said rotatable tubular member and the portion of said ribbonoverlying the outer surface of said rotatable tubular member and havinganother spirally wound portion extending through said fixed tubularmember, whereby when said ribbon moves longitudinally of said rotatabletubular member the portion of said wrapper overlying said rotatabletubular member moves along with said ribbon, and the portion of saidwrapper disposed within said fixed tubular member moves in the oppositedirection, the portion of said wrapper overlying said rotatable tubularmember and ribbon being adapted to engage the inner surface of saidplastic pipe during the formation thereof for moving said pipe therewithand being disengageable from said inner surface of said plastic pipeafter formation thereof.

7. In apparatus for making tape reinforced plastic pipe, at mandrelcomprising a longitudinally extending rotatable tubular member supportedadjacent only one end thereof, means for rotating said tubular memberabout its longitudinal axis, a plurality of circumferentially spacedrollers disposed adjacent one end of said tubular member and beingrotatable about axes extending transversely of the longitudinal axis ofsaid tubular member, another plurality of circumferentially spacedrollers disposed adjacent the other end of said tubular member and beingrotatable about axes extending transversely of the longitudinal axis ofsaid tubular member, a plurality of continuous ribbons having portionsoverlying the outer surface of said tubular member and having otherportions extending through said tubular member, each of said ribbonsoperatively engaging a roller at each end of said tubular member, anddrive means operatively connecting said plurality of rollers at said oneend of said tubular member to said tubular member for imparting rotationto said plurality of rollers at said one end of said tubular memberabout their respective axes in response to rotation of said tubularmember about its longitudinal axis whereby to impart longitudinal linearmovement to said plurality of ribbons relative to said tubular member,and a wrapper spirally wound on said tubular member and overlying saidfirst mentioned portion of said ribbon, whereby when said ribbons movelongitudinally of said tubular member said wrapper moves along with saidribbons, said wrapper being adapted to engage the inner surface of saidplastic pipe during the formation thereof for moving said pipe therewithand being disengageable from said inner surface of said plastic pipeafter formation thereof.

8. In appanatus for making tape reinforced plastic pipe, at mandrelcomprising a longitudinally extending rotatable tubular member supportedadjacent only one end thereof, means for rotating said tubular memberabout its longitudinal axis, a fixed longitudinally extending tubularmember disposed within said rotatable tubular member and spacedtherefrom, a plurality of oircumferentially spaced rollers disposedadjacent one end of said rotatable tubular member and being rotatableabout axes extending transversely of the longitudinal axis of saidrotatable tubular member, another plurality of cireumferentially spacedrollers disposed adjacent the other end of said rotatable tubular memberand being rotatable about axes extending transversely of thelongitudinal axis of said rotatable tubular member, a plurality ofcontinuous ribbuns, one for each roller at one end of said rotatabletubular member, each of said ribbons being in operative relationshipwith a roller at each end and having a portion overlying the outersurface of said rotatable tubular member and another portion extendingbetween said tWo tubular members, drive means operatively connectingsaid plurality of rollers at said one end of said rotatable tubularmember to said rotatable tubular member for imparting rotation to saidlast mentioned plurality of rollers about their respective axes inresponse to rotation of said rotatable tubular member about itslongitudinal axis whereby to impart longitudinal linear movement to saidplurality of ribbons relative to said rotatable tubular member, and acontinuous wrapper having a portion spirally wound over the outersurface of said rotatable tubular member and the portions of saidribbons overlying the outer surface of said rotatable tubular member andhaving another spirally wound portion extending through said fixedtubular member, whereby when ribbons move longitudinally of saidrotatable tubular member the portion of said wrapper overlying saidrotatable member moves along with said ribbon and the portion of saidwrapper disposed within said fixed tubular member moves in the oppositedirection, the portion of said wrapper overlying said rotatable tubularmember and ribbons being adapted to engage the inner surface of saidplastic pipe during the formation thereof for moving said pipe therewithand being disengageable fr m said inner surface of said plastic pipeafter formation thereof.

9. In apparatus for making tape reinforced plastic pipe, a mandrelcomprising a longitudinally extending tubular member, a plurality ofcircumfercnfially spaced continuous conveyor elements each having aportion overlying the outer surface of said tubular member and anotherportion extending through said tubular member, each of said conveyorelements being movable longitudinally f said tubular member, andspirally wound wrapper means on said tubular member in overlyingrelation with a part at least of the portion of the conveyor elementsoverlying the outer surface of said tubular member, whereby when saidconveyor elements move longitudinally of said tubular member saidspinally wound wrapper moves therewith to thereby form a longitudinallymovable pipe forming surface.

10. In apparatus for making tape reinforced plas i pipe, a mandrelcomprising a longitudinally extending tubular member, spirally woundwrapper means in overlying relation with a portion at least of saidtubular member for engaging said pipe in formation and for disengagingfrom said pipe, and means on said tubular member opcrativcly cngageablewith said wrapper means for advancing said wrapper means longitudinallyof said tubular member, whereby to advance said pipe.

11. In apparatus for making tape reinforced plastic pipe, comprising afirst longitudinally extending tubular member, a second longitudinallyextending tubular member disposed within said first tubular member andspaced therefrom, continuous wrapper means including a p rtion spirallywound about the outside of said first tubular member and a portionextending through the interior of said second tubular member, and meansdisposed exteriorly of said second tubular member and operativelyengageable with said first mentioned portion of said wrapper means formoving said first mentioned p rli n of said wrapper means longitudinallyof said first tubular member.

12. In apparatus for making tape reinforced plastic pipe, a mandrelcomprising a longitudinally extending tubular member supported adjacentone end thereof, a plurality of circumferentially spaced rollersdisposed adjacent one end of said tubular member and being rotatableabout axes extending transversely of the longitudinal axis of saidtubular member, another set of circumferentially spaced rollers disposedadjacent the other end of said tubular member and being rotatable aboutaxes extending transversely of the longitudinal axis of said tubularmember, a plurality of continuous conveyor elements, one for each rollerat one end of said tubular member, each of said conveyor elements beingin operative relationship with a roller at each end and having a portionoverlying the outer surface of said tubular member and another portionextending through said tubular member, drive means for impartingrotation to one set of rollers to impart longitudinal linear movement tosaid conveyor elements relative to said tubular member, continuouswrapper means having a portion spirally wound about the outer surfiaceof said tubular member and parts at least of the portions of saidconveyor elements overlying said outer surface and engaging said partsof said conveyor elements for movement therewith, said wrapper meanshaving another portion extending through said tubular member, the firstmentioned portion of said wrapper means being adapted to provide alongitudinally movable pipe forming surface for the pipe to be made bythe apparatus during the formation thereof.

13. In apparatus for making tape reinforced plastic pipe, a mandrelcomprising a longitudinally extending tubular member, continuousspirally wound wrapper means having a portion in overlying relation withth outer surface of said tubular member and another portion extendingthrough said tubular member, and means on said tubular memberoperatively engageable with said continuous wrapper means for advancingthe first mentioned portion of said wrapper means longitudinally of saidtubular member.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 2,331,696 Friedriohs et a1 Oct. 19, 1943 2,402,038Goldman et a1. June 11, 1946 2,674,557 Boggs Apr. 6, 1954 2,714,414 DeGanahl et a1 Aug. 2, 1955 2,723,705 Collins Nov. 15, 1955 2,742,931 DeGanahl Apr. 24, 1956 2,748,805 Winstead June 5, 1956 2,748,830 Nash etal. June 5, 1956 2,777,501 Fischer Jan. 15, 1957 2,828,239 Fischer Mar.25, 1958

